KR100756676B1 - Silicone bead, method for preparing the same, and thermoplastic resin composition using the same - Google Patents

Abstract

A method for preparing a polyorganosilsesquioxane fine particle, the polyorganosilsesquioxane fine particle prepared by the method, a thermoplastic resin composition containing the particle, and a diffusion plate for an LCD TV containing the particle are provided to use the polyorganosilsesquioxane fine particle as a diffusing agent for improving brightness and light resistance. A method for preparing a polyorganosilsesquioxane fine particle comprises the steps of mixing an organochlorosilane and an organotrialkoxysilane so as to make the concentration of organochlorosilane be 100-2,000 ppm; mixing the obtained one with water to prepare a transparent sol; and maintaining the pH of the sol to be 8-11. Preferably the organochlorosilane is represented by R1Si(OR2)_(3-x) Clx and the organotrialkoxysilane is represented by R1Si(OR2)3, wherein R1 is a C1-C6 alkyl group, a vinyl group or an aryl group; R2 is a C1-C5 alkyl group; and x is 1-3.

Description

Silicon-based fine particles, a method for producing the same, and a thermoplastic resin composition containing the particles {Silicone Bead, Method for Preparing the Same, and Thermoplastic Resin Composition Using the Same}

Field of invention

The present invention relates to a method for producing silicon-based fine particles. More specifically, the present invention relates to a novel method for producing polyorganosilsesquioxane fine particles, silicon-based fine particles produced by the method, and a thermoplastic resin composition to which the fine particles are applied.

Background of the Invention

Silicon-based fine particles such as silica and polyorganosilsesquioxane fine particles are widely used for various industrial purposes. Among them, the polyorganosilsesquioxane fine particles are widely used as additives for various resins or coating liquids due to their excellent compatibility with various polymer materials and organic solvents. Since polyorgano silsesquioxane microparticles | fine-particles are low in refractive index and excellent in compatibility with resin, they have attracted the spotlight recently as the diffusing agent of the diffusion plate used for LCD-TV. Such silicon-based fine particles can be easily manufactured by a general sol-gel method, but have a disadvantage in that expensive monomer raw materials are used and manufacturing costs are high because the yield per process time for producing the fine particles is low.

Japanese Patent No. 1,095,382 discloses a method for obtaining polyorganosilsesquioxane fine particles by carrying out a hydrolysis reaction and a condensation reaction using methyltrialkoxysilane containing 0.1 to 5% chlorine. Since it is not easy to control the reaction rate, due to problems such as intensified corrosion of the reactor due to hydrochloric acid is difficult to apply to the actual production process.

In Japanese Patent Laid-Open Nos. 1998-045914 and 2000-186148, a hydrolysis reaction is carried out using a mixture of methyltrialkoxysilane and water free of chlorine and an organic or inorganic acid as a catalyst and a condensation reaction with an aqueous alkali solution. Disclosed is a method of obtaining fine silsesquioxane microparticles. However, there is a problem in that the manufacturing cost increases because high-purity methyltrialkoxysilane which requires a separate purification process and a separate hydrolysis catalyst must be added for this purpose.

Accordingly, the present inventors generally use a small amount of an organoalkoxysilane in which the alkoxy group generated as a by-product in the preparation of the organoalkoxysilane is completely or partially substituted by the chlorine group as a hydrolysis reaction catalyst, and a mixture of the organotrialkoxysilane and water is highly efficient. By controlling the process conditions by using a mixer of the reaction rate was controlled to prepare a transparent sol in a short time, from this it was developed a new method for producing a simple and inexpensive polyorgano silsesquioxane fine particles. It was also found that the polyorganosilsesquioxane fine particles having a size of 2.5 to 3.5 μm obtained therefrom can exhibit excellent luminance and light resistance properties when used as a diffusing agent.

SUMMARY OF THE INVENTION An object of the present invention is to prepare a method for preparing polyorganosilsesquioxane fine particles easily and inexpensively by preparing a transparent sol within a short time by controlling a reaction rate of a mixture of organotrialkoxysilane and water using a high efficiency mixer. It is to provide.

Another object of the present invention is to provide polyorganosilsesquioxane microparticles which exhibit excellent luminance and light resistance when used as a diffusing agent.

Still another object of the present invention is to provide a thermoplastic resin composition containing the polyorganosilsesquioxane fine particles of the present invention.

Still another object of the present invention is to provide a diffusion plate for LCD-TV having excellent brightness and light resistance using the thermoplastic resin composition.

Both the above and other objects of the present invention can be achieved by the present invention described below.

Summary of the Invention

In the method for producing silicon-based fine particles of the present invention, the organotrialkoxysilane in which the alkoxy group is wholly or partially substituted by the chlorine group is mixed with the organotrialkoxysilane so as to have a concentration of 100 to 2,000 ppm, and the mixture and water are mixed with a high efficiency mixer. A method for producing polyorganosilsesquioxane microparticles, comprising the steps of obtaining a transparent sol in a short time by mixing and maintaining the pH at 8-11.

Further, among the fine particles obtained at this time, the fine particles having an average particle diameter of 2.5 to 3.5 μm are characterized by excellent luminance and light resistance characteristics when used as a diffusing agent.

Detailed Description of the Invention

The silicone fine particles of the present invention are mixed with an organotrialkoxysilane such that the alkoxy group is entirely or partially substituted by a chlorine group to a concentration of 100 to 2,000 ppm, and the mixture and water are mixed to obtain a transparent sol. And it is a microorgano silsesquioxane microparticles | fine-particles manufactured by the step of maintaining pH at 8-11.

The organotrialkoxysilane used in the present invention is represented by the following formula (1):

R ¹ Si (OR ² ) ₃ (1)

In the formula, R ¹ represents an alkyl group having 1 to 6 carbon atoms, a vinyl group, or an aryl group, and R ² represents an alkyl group having 1 to 5 carbon atoms. It is preferable that R <^1> is a methyl group, an ethyl group, and a phenyl group, and it is preferable that R <^2> is a methyl group, an ethyl group, a propyl group, and a butyl group. In particular, it is most preferable from an industrial point of view that R ¹ and R ² are methyl groups.

The organotrialkoxysilane of Formula (1) is preferably used in an amount of 5 to 50% by weight based on the total reaction solution, and more preferably in an amount of 10 to 30% by weight for controlling the reaction yield and the average particle size.

The organochlorosilane in which the alkoxy group is wholly or partially substituted by the chlorine group is represented by the following formula (2):

R ¹ Si (OR ² ) _3-x C _lx (2)

In formula, R <^1> represents a C1-C6 alkyl group, a vinyl group, or an aryl group, R <^2> represents a C1-C5 alkyl group, and x has a range of 1-3. It is preferable that R <^1> is a methyl group, an ethyl group, and a phenyl group, and it is preferable that R <^2> is a methyl group, an ethyl group, a propyl group, and a butyl group. In particular, it is most preferable from an industrial point of view that R ¹ and R ² are methyl groups. In addition, it is most preferable that all the alkoxy groups are organotrichlorosilane substituted by the chlorine group.

The organochlorosilane in which the alkoxy group of the said Formula (2) is wholly or partially substituted by the chlorine group is mixed with the organotrialkoxysilane of the said Formula (1) in 100-2,000 ppm content. If the content is less than 100 ppm, the hydrolysis reaction does not proceed sufficiently under strong mixing conditions, making it difficult to obtain fine particles having a desired particle size, and the content of 2,000 ppm or more difficult to control the rate of hydrolysis reaction, making it difficult to obtain fine particles having a desired particle size. As a result, the entire gelation reaction proceeds, making it impossible to obtain a particulate product. In addition, problems such as impurity cleaning and reactor corrosion due to excessive chlorine content will occur.

A transparent sol is obtained by mixing a mixture of an organochlorosilane in which the alkoxy group represented by the formula (2) is wholly or partially substituted with a chlorine group with the organotrialkoxysilane of the formula (1) with water using a high efficiency mixer. To manufacture. The mixing efficiency is very important in preparing a transparent sol. In particular, in the case of using an organochlorosilane in which a small amount of alkoxy group of 100 to 2,000 ppm is substituted by a chlorine group, the rate of hydrolysis reaction is remarkably reduced, so that the organotrialkoxysilane and water are mixed by using a high efficiency mixer. The reaction area should be kept large enough.

A common type of mixer uses anchors, piddlers, paddles, propellers, ribbon type impellers. When using this type of mixer, it is necessary to increase the amount of reaction catalyst used for the hydrolysis reaction, increase the reaction temperature, and extend the reaction time due to the decrease in the mixing efficiency. Will cause. In addition, the stirring speed must be very high, which causes a lot of difficulties in actual mass production. Increasing the stirring speed causes difficulty in controlling bubble generation and particle size distribution due to an increase in process cost and excessive vortex generation.

Therefore, it is preferable to manufacture a transparent sol using a high efficiency mixer. The high efficiency mixer may be a high speed emulsifier / dispersion equipment such as a homomixer, a homogenizer, a microfluidizer, or a flat impeller and a baffle plate. It is preferable to use a stirring device in the form of a combination. Equipment such as homomixers, homogenizers and microfluidizers enable high efficiency mixing or liquid-liquid mixing in a short time by using high shear force, impact force, shock waves generated during cavitation, and the like. It is more preferable to use an operating condition of 5,000 rpm or more, and it is more preferable to use an operating condition of 5,000 psi or more of a homogenizer or a microfloodizer. The combination of a flat impeller and a baffle plate enables efficient mixing even at low speed stirring conditions. The flat impeller preferably has a width of 50% or more of the diameter of the reactor, and more preferably has a hole parallel to the stirring axis direction.

After preparing a transparent sol using the said highly efficient mixer, the polyorgano silsesquioxane microparticles | fine-particles are obtained by adjusting pH to 8-11. When the pH is less than 8, the formation of the microparticles takes a very long time or is difficult to form the microparticles, and when the pH is 11 or higher, a problem of dissolving again after the formation of the microparticles occurs. More preferably, the pH is adjusted to 9-10. In order to adjust pH to 8-11, general basic aqueous solution is used, and it is preferable to use aqueous solutions, such as alkali metal, alkaline-earth metal, hydrogen carbonate, and ammonia.

Thereafter, the final fine particles are obtained through filtration, washing with water and drying. It is preferable to use a spray dryer or a spin flash dryer for drying because it prevents agglomeration between particles and thus can easily obtain fine particles in a powder state without a separate disintegration step.

The polyorganosilsesquioxane fine particles having a size of 0.1 to 10 μm can be obtained through the above-described manufacturing method. The polyorganosilsesquioxane fine particles thus obtained may be vinyl chloride-based resin, styrene-based resin, or styrene-acrylonitrile-based resin. , And may be blended with thermoplastic resins such as acrylic resins, acrylic-styrene resins, ester resins, ABS resins, and polycarbonate resins to be applied to the diffusion plate.

That is, when the polyorganosilsesquioxane fine particles are added to thermoplastic resins such as polystyrene, polymethyl methacrylate, poly (methyl methacrylate-styrene) copolymer, polycarbonate, and the like, the transmittance is lowered. It can be used as a diffusion agent of the diffusion plate used.

Among the polyorganosilsesquioxane fine particles obtained through the above production method, when using polyorganosilsesquioxane fine particles having an average particle diameter of 2.5 to 3.5 μm as a diffusion agent, the characteristics of diffusion plate such as transmittance, haze, brightness, light resistance, etc. It is expressed well. The polyorganosilsesquioxane fine particles having a particle size of 2.5 to 3.5 μm are preferably added in an amount of 0.1 to 10 parts by weight, and most preferably 0.1 to 2 parts by weight.

The invention can be better understood by the following examples, which are intended for the purpose of illustration of the invention and are not intended to limit the scope of protection defined by the appended claims.

Example 1

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 200 g of this mixed solution was mixed with 1,800 g of ion-exchanged water. Then, using a homomixer for 1 minute high speed mixing at 10,000 rpm, ammonia water was added to adjust the pH to 9.7 and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Example 2

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 280 g of this mixed solution was mixed with 1,720 g of ion-exchanged water. Then, using a homomixer at high speed mixing at 10,000 rpm for 1 minute, and ammonia water was added to adjust the pH to 9.6 and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Example 3

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 400 g of the mixed solution was mixed with 1,600 g of ion-exchanged water. Then, using a homomixer at high speed mixing at 10,000 rpm for 1 minute, and ammonia water was added to adjust the pH to 9.6 and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Example 4

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 200 g of this mixed solution was mixed with 1,800 g of ion-exchanged water. Thereafter, the microfluidizer was treated once at 10,000 psi, and the pH was adjusted to 9.7 by adding ammonia water and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Example 5

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 200 g of this mixed solution was mixed with 1,800 g of ion-exchanged water. Thereafter, a high speed mixing treatment was performed at 10,000 rpm for 1 minute using a homomixer, and the treatment was performed once at 10,000 psi using a microfluidizer. Then, the pH was adjusted to 9.7 by adding ammonia water, and then maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Example 6

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 280 g of this mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to a glass reactor equipped with a baffle plate and mixed for 30 minutes at 70 rpm using a plate-type impeller having a width of 60% of the inner diameter of the reactor. Then, the pH was adjusted to 9.5 by adding ammonia water, and then maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Example 7

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 280 g of this mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to a glass reactor equipped with a baffle plate and mixed for 90 minutes at 90 rpm using a plate-type impeller having a width of 60% of the inner diameter of the reactor. Then, the pH was adjusted to 9.1 by adding ammonia water, and then maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Comparative Example 1

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 280 g of this mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to the glass reactor and mixed for 30 minutes at 70 rpm using a general anchor impeller. Then, the pH was adjusted to 9.4 by adding ammonia water and then maintained at room temperature for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Comparative Example 2

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 500 ppm, 280 g of this mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to the glass reactor and mixed for 150 minutes at 150 rpm using an impeller of a general anchor type. Then, the pH was adjusted to 9.3 by adding ammonia water and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Comparative Example 3

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 50 ppm, 280 g of the mixed solution was mixed with 1,720 g of ion-exchanged water. Then, the mixed solution was added to the glass reactor, and the mixture was treated for 30 minutes at 70 rpm using an impeller of a general anchor type. Then, the pH was adjusted to 9.3 by adding ammonia water and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Comparative Example 4

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 6,000 ppm, 280 g of the mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to the glass reactor and mixed for 30 minutes at 70 rpm using a general anchor impeller. Then, the pH was adjusted to 9.4 by addition of ammonia water and maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Comparative Example 5

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 50 ppm, 280 g of the mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to a glass reactor equipped with a baffle plate and mixed for 30 minutes at 70 rpm using a plate-type impeller having a width of 60% of the inner diameter of the reactor. Then, the pH was adjusted to 9.5 by adding ammonia water, and then maintained for 4 hours. Thereafter, white fine powder was recovered by filtration, washing with water and drying with a spray dryer.

Comparative Example 6

After methyltrichlorosilane was mixed with methyltrichlorosilane to a concentration of 6,000 ppm, 280 g of the mixed solution was mixed with 1,720 g of ion-exchanged water. Thereafter, the mixed solution was added to a glass reactor equipped with a baffle plate and mixed for 30 minutes at 70 rpm using a plate-type impeller having a width of 60% of the inner diameter of the reactor. To obtain fine particles.

The fine particles obtained through the above process are shown in Table 1 by evaluating the physical properties through the following method.

(1) Average particle size and monodispersity: After redispersing the recovered fine particles in water, the particle size area over 1 μm was analyzed using Beckman Coulter Multisizer, and the particle size area under 1 μm was analyzed using Malvern size analyzer. It was. Monodispersity is defined by dividing the standard deviation by the mean particle diameter. Expressed by value.

(2) Diffusion Efficiency: Pellets were mixed by mixing 100 parts by weight of polystyrene resin with 1 part by weight of EXL-5136 by Rohm & Hass, and 1 part by weight of the fine particles recovered in the examples and comparative examples using a twin screw extruder having a diameter of 45 mm. A flat specimen of 1.5 mm thickness was prepared at a molding temperature of 210 ° C. in a 10 oz injection machine. Transmittance and haze were evaluated using the prepared flat specimens.

(3) Luminance and light resistance: Luminance was evaluated using a flat plate specimen prepared in the same manner as above. In addition, after measuring the initial YI using a color difference meter, YI was measured after ultraviolet irradiation for 24 hours, and ΔYI was calculated from this change value to evaluate light resistance.

As shown in Examples 1 to 7 of Table 1, a mixture of methyltrichlorosilane and methyltrimethoxysilane was mixed with a high efficiency mixer, and then adjusted to pH 8-11 to prepare polyorganosilsesquioxane fine particles. In this case, by controlling the process conditions, fine particles of 0.1 to 10 탆 could be easily produced in a short time. Particularly, when polymethylsilsesquioxane fine particles having an average particle diameter of 2.5 to 3.5 µm were used as the diffusion agent for the diffusion plate, the diffusion characteristics and the luminance characteristics were expressed in the most balanced manner, and the YI and the light resistance characteristics were excellent. Through 2 and 6 it was confirmed.

The present invention provides a method for easily and inexpensively preparing polyorganosilsesquioxane fine particles by preparing a transparent sol in a short time by controlling a reaction rate of a mixture of organotrialkoxysilane and water using a high efficiency mixer. The present invention provides polyorganosilsesquioxane microparticles that exhibit excellent brightness and light resistance when used as a diffusing agent, and has the effect of providing a thermoplastic resin composition containing the polyorganosilsesquioxane microparticles.

Simple modifications or changes of the present invention can be easily carried out by those skilled in the art, and all such modifications or changes can be seen to be included in the scope of the present invention.

Claims (11)

(a) mixed with organotrialkoxysilane such that the organochlorosilane is at a concentration of 100-2,000 ppm; (b) mixing water into the mixture to obtain a clear sol; And (c) maintaining the pH of the mixed solution at 8-11; Method for producing a polyorganosilsesquioxane microparticles comprising the step. The method for producing polyorganosilsesquioxane fine particles according to claim 1, wherein the organotrialkoxysilane is represented by the following formula (1): R ¹ Si (OR ² ) ₃ (1) In the formula, R ¹ represents an alkyl group having 1 to 6 carbon atoms, a vinyl group, or an aryl group, and R ² represents an alkyl group having 1 to 5 carbon atoms. The method for producing polyorganosilsesquioxane fine particles according to claim 2, wherein the organotrialkoxysilane of the formula (1) is used in an amount of 5 to 50% by weight based on the total reaction solution. The method for preparing polyorganosilsesquioxane fine particles according to claim 1, wherein the organochlorosilane is represented by the following formula (2): R ¹ Si (OR ² ) _3-x Cl _x (2) In formula, R <^1> represents a C1-C6 alkyl group, a vinyl group, or an aryl group, R <^2> represents a C1-C5 alkyl group, and x is a range of 1-3. The method for producing polyorganosilsesquioxane fine particles according to claim 1, wherein the organochlorosilane is organotrichlorosilane. The method for producing polyorganosilsesquioxane fine particles according to claim 1, wherein after the step (c), the reaction solution is filtered, washed with water and dried to obtain fine particles having an average particle size of 0.1 to 10 µm. The method of claim 1, wherein the mixture is mixed with water by using a homomixer, a homogenizer, a microfluidizer alone or in combination, or a plate-type impeller having a width of 50% or more of a reactor diameter, and a plurality of reactor lengthwise directions. A method for producing polyorganosilsesquioxane fine particles, which comprises using a stirring device composed of a baffle plate. Polyorganosilsesquioxane microparticles | fine-particles manufactured by the method of any one of Claims 1-7, and have an average particle diameter of 0.1-10 micrometers. 9. The polyorganosilsesquioxane microparticles according to claim 8, wherein the microparticles have an average particle diameter in the range of 2.5 to 3.5 mu m and exhibit excellent brightness and light resistance properties when applied as a diffusion agent to a thermoplastic resin. A thermoplastic resin selected from the group consisting of vinyl chloride resins, styrene resins, styrene-acrylonitrile resins, acrylic resins, acrylic-styrene resins, ester resins, ABS resins, and polycarbonate resins, and the polio of claim 8. A thermoplastic resin composition comprising the organosilsesquioxane fine particles. A diffusion plate for an LCD-TV comprising 0.1 to 10 parts by weight of the polyorganosilsesquioxane fine particles according to claim 9 with respect to 100 parts by weight of the thermoplastic resin.